supply. The tissues become ischemic and hypoxic leading to inflammation, edema and rhabdomyolysis.
Horses with a
muscle or body mass and those on a diet high in simple carbohydrates
are more likely to experience post-anaesthetic myoneuropathy.
The area affected by post-anaesthetic myoneuropathy is related to the positioning of the horse during surgery. If the horse was in recumbency the muscles most affected will be the and the muscles.
If the horse was in
recumbency the intercostal muscles, the muscles will be most affected in the
and the
body and the temporalis and masseter muscles will be most affected in the head.
Depending on the extent of necrosis the horse may not be able to rise on recovery, it may be anxious, sweating, weak and muscle sore, as well as have an increased TPR. In severe cases the horse may exhibit signs of kidney damage such as , which is described as dark, coffee-coloured urine. Blood chemistry will reveal elevated circulating levels of the CK and AST muscle enzymes.
Diagnosis is made through clinical signs and symptoms, recent history of surgery and through blood chemistry.
Treatment includes the administration of fluids and NSAID’s other than phenylbutazone in the acute stage. Once the horse is comfortable and blood chemistry has returned to normal levels, massage and hydrotherapy may help in the repair of damaged tissue. Prevention of post-anaesthetic myoneuropathy includes the proper positioning of the horse during surgery and the use of adequate on surgical beds. It is also recommended that carbohydrate intake is restricted before surgical procedures. Prognosis for horses affected by post-anaesthetic myoneuropathy is variable depending on the degree of muscle damage and the amount of kidney damage. Those individuals with little muscle damage and no kidney damage have a good prognosis while those with extensive muscle damage and any degree of kidney damage have a guarded to poor prognosis. Exertional Rhabdomyolysis Exertional rhabdomyolysis is commonly known by a number of different names including “tying- up”, “azoturia” and “exertional myopathy”.
The exact cause of exertional rhabdomyolysis is
, but there are many factors
that are thought to contribute to the onset of the condition.
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